Multi-band cellular service over catv network

ABSTRACT

A CATV network distributing signals below 860 MHz is modified with a secondary transmission bi-directional capability above 860 MHz by adding filters to separate modified mobile-communications frequencies (above 860 MHz) from typical CATV services (below 860 MHz). CATV subscriber termination points function as extremely localized ultra-miniature cell sites within a building. Multiple cellular networks and possibly multiple providers are simultaneously accommodated over a CATV network. The modified network simultaneously handles traffic in combinations of known cellular air interface standards such as: UMTS, GSM, TDMA, CDMA and PDC. Cellular mobile radio terminals do not have to be modified. Signals traverse on non-utilized CATV frequencies. CATV active elements are modified, and new components are provided. A Cable Mounted Cellular Adapter at the CATV outlet acts as a transmit/receive unit and frequency translator for the cellular signals.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of National Stage application Ser.No. 10/476,412 filed Apr. 20, 2004, which claims the benefit of PCTApplication No. PCT/US02/11867, filed May 1, 2002, which claims priorityfrom Provisional Application No. 60/287,705; filed May 2, 2001. Theentire disclosures of the prior applications, application Ser. Nos.10/476,412, PCT/US02/11867 and 60/287,705 are hereby incorporated byreference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This description relates to a new system and topology for providingcellular service in multiple bands by using a cable TV network. Thesystem can improve the in-building coverage and the total availablecapacity of different cellular networks, using the same CATV network.These cellular networks may have multiple air interfaces, differentfrequency bands and may be operated, simultaneously, by differentcellular service providers. As used herein, the terms “mobile”,“cellular”, and “wireless” are meant generically to refer to radiosystems or networks such as UMTS, GSM900, GSM1800, PCS1900, TDMA800,CDMA800, CDMA2000 1X/3X, or PDC. Other types are known, and still othertypes may be hereafter developed, and it will be appreciated that“mobile”, “cellular”, and “wireless” are terms intended to include allsuch systems.

In particular, this description relaftes to an extension to conventionalmobile radio networks using cable TV or HFC (Hybrid Fiber Coax) networks(and the like, all referred to generally as CATV networks, hereafter).To be even more specific, there is described an approach to merging CATVnetworks into mobile radio networks to provide improved voice & dataservices and coverage, while enhancing network capacity; to providingin-building access for any combination of mobile radio terminals, in amobile radio network; to combining and carrying any combination ofmobile radio signals on the CATV system, without interfering with eachother, or the CATV service.

2. Related Work

The basic theory by which mobile radio and cellular networks operate iswell known. Geographically distributed network access points, eachdefining cells of the network, characterize cellular radio networks. Thegeographically distributed network access points are typically referredto as base stations BS or base transceiver stations BTS, and includestransmission and reception equipment for transmitting signals to andreceiving signals from mobile radio terminals (MT). Here, a MT includesnot only a normal cellular phone, but any device capable of performingcellular communications. Each cell (or sector) is using only part of thetotal spectrum resources licensed to the network operator, but the samecapacity resources (either frequency or code), may be used many times indifferent cells, as long as the cell to cell interference is kept to awell defined level. This practice is known as the network reuse factor.The cells may be subdivided further, thus defining microcells. Each suchmicrocell provides cellular coverage to a defined (and usually small)area. Microcells are usually limited in terms of their total availablecapacity.

One problem needing to be solved is the inability of present frequencyor code reuse techniques (sectorization and cell-area subdivision) todeal with the “third dimension” problem. Cellular networks have no meansto deal with the problem of user terminals at higher-than-usualelevations, e.g. upper floors of high-rise office or residentialbuildings. The overall demand for mobile services has caused cellularnetwork operators to develop an intensive network of BTSs in urbanareas. This has improved spectrum utilization (increased networkcapacity) at ground level, but has aggravated the problem in high-risebuildings where MTs now ‘see’ several BTSs on the same frequency orcode.

Cells in a cellular radio network are typically connected to ahigher-level entity, which may be referred to as a mobile switchingcenter (MSC), which provides certain control and switching functions forall the BTSs connected to it. The MSCs are connected to each other, andalso to the public switched telephone network (PSTN), or may themselveshave such a PSTN interface.

The conventional implementation of mobile radio networks has had someimportant limitations. When operating above 1 GHz, it is necessary in aconventional mobile radio network to build numerous base stations toprovide the necessary geographic coverage and to supply enough capacityfor high-speed data applications. The base stations require an importantamount of real estate, and are very unsightly.

Another limitation is that, since cellular towers are expensive, andrequire real estate, it is economically feasible to include in a networkonly a limited number of them. Accordingly, the size of cells might bequite large, and it is therefore necessary to equip the mobile radioterminals with the ability to radiate at high power so as to transmitradio signals strong enough for the geographically dispersed cellulartowers to receive.

As the cell radius becomes larger, the average effective data rate peruser in most packet based protocols decreases accordingly and thehigh-speed data service might deteriorate.

Yet another limitation to cellular radio networks as conventionallyimplemented is that the cellular antennas are typically located outsideof buildings, even though it would be highly beneficial to providecellular service inside buildings. The penetration of cellular signalsfor in-building applications requires high power sites, or additionalsites or repeaters to overcome the attenuation inherent with in-buildingpenetration. As frequency increases, the in-building signal leveldecreases accordingly. Because the base station antennas are locatedoutside of buildings, it is difficult for mobile radio terminals totransmit signals strong enough to propagate effectively from inside ofthe building to outside of the building. Therefore, the use of mobileterminals inside buildings results in reduced data rate and consumes asubstantial amount of the limited battery time.

Yet another limitation of mobile radio networks as conventionallyimplemented is the inherent limited capacity of each and every BTS toprovide voice and data service. This capacity shortage is due to the waythe spectrum resources are allocated to each BTS. To provide forreasonable voice and data quality, each BTS can use only a part of thetotal spectrum resources owned by the cellular operator. Other BTSs canreuse the same part of the spectrum resources as a given BTS, but apattern of geographic dispersion has to be respected. This is called acode reuse factor for CDMA based technologies, and frequency reusefactor for TDMA based technologies.

Because CATV is so ubiquitous today, even in rural areas, it becomesvery interesting to attempt to overcome the above identified limitationsof cellular systems by taking advantage of the bandwidth of the CATVnetworks.

FIG. 1 shows a CATV system, in highly simplified schematic form. In theCATV system, the CATV head end is connected to a CATV cable network. TheCATV cable network includes various equipment, such as amplifiers. MostCATV networks today are bidirectional. That is to say, communicationsfrom the CATV head end toward the end user (i.e., downstreamcommunications) and also communications from the end user to the CATVhead end (i.e., upstream communications) are possible.

The CATV network shown in FIG. 1 is a bidirectional system. The CATVamplifiers are bidirectional as well. Upstream communications arecarried in a relatively narrow band of 5-45 MHz. Downstreamcommunications are carried in a relatively wide band of 50-750 MHz or50-860 MHz, depending on the particular system.

The communications traveling downstream from the CATV head end arepassed on through a tree-shaped network to a set-top box (STB). The STBconnects to the television set. Of course, it is quite possible that thetelevision set includes the appropriate equipment to allow theconnection of the cable without the use of a STB. Likewise, there mightbe a cable modem or other related device. For convenience, herein, STBis used to mean any devices of this kind.

FIG. 2 shows a conventional approach to carrying bidirectional cellularcommunications over such a network. In this approach, the public landmobile network (PLMN) is connected to the cable system via an interfaceI/F. Downlink communications from the PLMN are carried through the CATVamplifiers, and the CATV network through a remote antenna driver (RAD).The RAD takes the downlink communications and broadcasts them to an MT.

Upstream communications from the mobile terminal travel through the RAD,and through the upstream portion of the bandwidth, through the CATVamplifiers, through the I/F, and then to the PLMN. Naturally, frequencyconversion is necessary at the RAD so that the uplink communications canbe put into the upstream bandwidth of the CATV network.

The prior approaches for carrying wireless signals over the CATV networkinclude re-arranging or re-packaging the original radio signal to fitinto the existing CATV standard frequencies (5-45 MHz and 50-750/860MHz) and channels. This is typically done by active elements, which up-and down-convert the wireless frequencies to match the known standardCATV operational frequencies in the standard CATV upstream anddownstream frequencies. Using the standard CATV channels, however,reduces the available bandwidth of the CATV operators in providingvideo, data and voice according the common CATV standards like DOCSISand DVB.

Such approaches have all been disadvantageous, however. In particular,if one wishes to re-arrange and re-pack the full UMTS frequency band(1920-1980 MHz, 2110-2170 MHz) into the standard CATV channels, onefinds that the UMTS uplink bandwidth (60 MHz) is too large, and henceimpossible for the CATV upstream (40 MHz) to carry. Even if a smallerUMTS bandwidth were to be carried over the CATV upstream, this woulddramatically reduce the scarce upstream CATV resource. Some patentdocuments representing such disadvantageous approaches are nowsummarized.

U.S. Pat. Nos. 5,802,173 and 5,809,395 (related patents) describe aradiotelephony system in which cellular signals are carried over a CATVnetwork. However, uplink cellular communications are frequency convertedto “in the range 5 to 30 MHz”. Such a conversion is necessary becausethe CATV network is normally frequency-divided into two bands: a highband which handles downstream transmission (head-end to hub tosubscriber) and a low band which handles upstream transmission(subscriber to hum to head end). In other words, any upstream signals orcommunications over about 45 MHz are filtered out by the CATV networkitself as a part of the normal operation of the network. Under the '173approach, upstream communications all must be fit into the low band(i.e., in “a portion of the frequency spectrum allocated in the CATVsystem for upstream communications”).

U.S. Pat. No. 5,828,946 describes a CATV based wireless communicationsscheme. Under the '946 approach, to avoid multiple outdoor cellularreceptions from causing noise over the CATV network, only the signalsreceived at a sufficient power level are converted and sent upstream.

U.S. Pat. No. 5,822,678 acknowledges that the frequency-divided natureof CATV networks is a problem. In particular, the '678 patent teachesthat the limited bandwidth available “within the frequency band of fivemegahertz to 40 megahertz” poses “a problem with using the cable plantto carry telephonic signals.” To solve this problem, the '678 approachis that “currently existing frequency allocations for cable televisionare redefined.” That is to say, the division between high and low bandsin a CATV network is moved from about 40 MHz to several hundredmegahertz higher. This simplistic approach is highly disadvantageousbecause it requires replacement of substantial amounts of equipment inany CATV network. Such an expensive approach has not yet been adoptedfor actual use.

U.S. Pat. No. 5,638,422, like the previously mentioned documents,teaches carrying uplink cellular communications in “the return path ofthe CATV system, i.e. 5 to 30 MHz, for telephone traffic in the returndirection.” Furthermore, downlink cellular communications aredisadvantageously carried in “the forward spectrum, i.e. 50 to 550 MHzof the CATV system”. This interferes with CATV signals, and isproblematic for the CATV operator, who must move existing programming toother parts of the spectrum to make room for downlink cellular signals.

U.S. Pat. No. 6,223,021 teaches how to use programmable remote antennadrivers to provide augmented cellular coverage in outdoor areas. Forexample, during morning rush hour, the remote antennas are tuned to onefrequency set and to another during evening rush hour. Thus, outdoorcommunications can be flexibly augmented. The remote antenna drivers andtheir antennas are hung from outdoor CATV cables. The '021 patent doesnot describe how to solve the problem of limited upstream bandwidth foruplink cellular communications.

U.S. Pat. No. 6,192,216 describes how to use a gain tone from remoteantenna locations, sent over a CATV network, to determine a proper levelof signal at which each remote antenna location should transmit.

U.S. Pat. No. 6,122,529 describes the use of outdoor remote antennas andremote antenna drivers to augment an existing cellular coverage area,but only in areas where outdoor cellular antennas provide no coverage.The signal of a given BTS sent to a cellular antenna tower is simulcastover the remote antennas to overcome “blind” areas.

U.S. Pat. No. 5,953,670 describes how to use remote antenna drivers aswell, but adopts the above-identified approach of sending uplinkcellular communications in the low CATV band.

SUMMARY OF THE INVENTION

It is therefore an object to overcome the above-identified limitationsof the present mobile radio networks, and the above-identifieddisadvantages of the related attempts to integrate standard mobile radionetworks with CATV networks.

According to one aspect of the system, there is provided an extension toconventional mobile radio networks whereby a CATV network is enabled totransport multi-band bidirectional mobile radio traffic. According toanother aspect of the system, there is provided a CATV network capableof handling traffic in a pre-determined multi-band configuration ofvarious mobile radio systems from various providers, simultaneously,without degrading the CATV services or the cellular services.

To achieve the above and other objects, the CATV network functions as anaccess element of the mobile radio networks, namely in the RFpropagation-radiation section. According to the system described herein,the capabilities of existing CATV networks are substantially preserved,and the mobile radio terminals do not have to be modified. That is tosay, the signals sent according to the radio communications protocoltraverse the CATV network on non-utilized CATV frequencies above thefrequencies used for CATV programming, but reach the mobile terminalsexactly at the same standard frequency as was originally produced by thebase station.

The radio frequencies and channel structures of the mobile radionetworks and CATV networks are different. The CATV network is modifiedso as to permit the propagation of the RF signals of the mobile radionetwork, frequency translated to propagate over the CATV system in aband higher than the CATV programming.

Such a frequency band is not used at all by the CATV operators, but itmay be used to carry combinations of cellular systems signals byproperly upgrading the CATV infrastructure. Thus, it is an objective toprovide a system capable of transporting more than one cellular systemsimultaneously (in other words, multi-band cellular service).

A conventional CATV network is a two-way network having a tree andbranch topology with cables, amplifiers, signal splitters/combiners andfilters. According to one aspect of the system, the cables and otherpassive components like signal splitters/combiners are not modified, butthe active elements are. Thus, the system includes new components for aCATV system that permit to overlaying a multi-band, multi-standard,bi-directional communication system. The modified components allow bothtypes of signals (the CATV up and down signals and the cellular up anddown signals) to be carried by the network simultaneously in a totallyindependent manner (without any cross-coupling which can be a source ofan unacceptable interference).

It is important to note that the cables (fiber and coaxial) used in CATVnetworks are not severely limited as to bandwidth. Practical CATVnetworks are bandwidth limited by the bandwidth and signal loadinglimitations of practical repeater amplifiers. CATV networks now usefilters to segment cable spectrum into two bands—one for upstreamcommunications and the other for downstream communications. By addingduplexers and filters to provide additional spectrum segmentation itallows additional amplifiers to handle upstream and downstream cellularnetwork traffic.

According to another aspect of the system, there is provided a componentthat acts as a transmit/receive antenna and frequency translator for anycombination of cellular signals, and as a CATV input/output unit for theCATV network. The component may also provide controlled attenuation inthe downlink. Most of the existing CATV video signals are alreadylimited to frequencies under 750 MHz (some CATV networks go up to 860MHz) so the standardized cellular signals are translated to above thislimit. The different types of signals (CATV & Cellular) can coexistwithin the same CATV cable due to this fact.

The CATV network is thus modified in a way that permits the CATVtransmissions to be maintained in their original format and frequencyassignments. The modifications to the CATV network itself can be madeusing only linear components such as filters and amplifiers. Themodifications are simple, robust and affordable.

The invention is taught below by way of various specific exemplaryembodiments explained in detail, and illustrated in the enclosed drawingfigures. It will be appreciated, however, that the invention is muchbroader than the examples described below, and the examples are providedfor the sake of teaching the invention in its presently preferredembodiment. The appended claims are intended to describe the actualscope of the invention.

BRIEF DESCRIPTION OF THE DRAWING FIGURES

The drawing figures depict, in highly simplified schematic form,embodiments reflecting the principles of the invention. Many items anddetails that will be readily understood by one familiar with this fieldhave been omitted so as to avoid obscuring the invention. In thedrawings:

FIG. 1 shows a conventional CATV network.

FIG. 2 exemplifies prior approaches to carrying cellular signals over aCATV network.

FIG. 3 shows an upgraded cellular cable network according to oneembodiment of the invention.

FIG. 4 shows a schematic of a cellular bypass device according to anembodiment of the invention.

FIG. 5 shows a network coupling device and a cable mount cellularantenna according to an embodiment of the invention.

FIG. 6 shows a cellular entrance module for a dual band system accordingto an embodiment of the invention.

FIG. 7 shows one frequency assignment scheme for a dual band cellularsystem.

FIG. 8 shows an alternative frequency assignment scheme for a dual bandcellular system.

FIG. 9 shows a frequency converter (UP/Down converter, or UDC) for adual band cellular system with frequencies as in FIG. 7 or 8.

FIG. 10 shows a cellular entrance module for a triple band systemaccording to an embodiment of the invention.

FIG. 11 shows a frequency assignment scheme for a triple band cellularsystem.

FIG. 12 shows a frequency converter for a triple band cellular system.

FIG. 13 shows a cellular entrance module for a six band system accordingto an embodiment of the invention.

FIG. 14 shows a frequency assignment scheme for a six band cellularsystem.

FIG. 15 shows a frequency converter for a six band system.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The invention will now be taught using various exemplary embodiments.Although the embodiments are described in detail, it will be appreciatedthat the invention is not limited to just these embodiments, but has ascope that is significantly broader. The appended claims should beconsulted to determine the true scope of the invention.

FIG. 3 shows a CATV segment in a hybrid wireless/CATV system in whichthe invention is implemented. In FIG. 3, the wireless uplink anddownlink frequencies are not converted into the normal bandwidth of theCATV system. Instead, the uplink and downlink frequencies are convertedinto a part of the bandwidth above the CATV programming. That is to say,wireless communications are all carried above, for example, 860 MHz.

The CATV amplifier normally passes along only frequencies in the 5-45MHz band for upstream communications, and filters out all otherfrequencies passing upstream. The CATV amplifier normally passes alongonly frequencies in the 50-750/860 MHz band for downstreamcommunications, and filters out all other frequencies passingdownstream. This poses a problem to carrying the cellular communicationsin a band above the normal CATV programming.

To overcome this problem, a cellular bypass (CBP) is installed at eachactive point or component (such as a CATV amplifier, trunk amplifier,line extender, distribution module, and the like). The CBP includes acellular amplifier and bypass devices (BPD). The CBP thus passes theuplink and downlink communications around the CATV amplifiers so thatthe cellular communications are not filtered out by the CATV amplifiers.

At each end user location, there is provided a network coupling device(NCD) and a cable mount cellular antenna (CMCA). The NCD passes CATVtraffic to and from the STB (or television set or other component, if noSTB is used), and passes cellular traffic to and from the CMCA. The enduser location may be thought of as an indoor termination point of theCATV network.

The traffic from the head end is combined with traffic from PLMN A andPLMN B via a cellular entrance module (CEEM, described below). PLMN Aand PLMN B are different types of systems, such as GSM1800 and UMTS. Thetraffic from these two different systems may be thought of as multi-bandtraffic or multi-band cellular communications. As used herein,“multi-band” means traffic of more than one system (although suchsystems might conceivably be of the same type, such as UMTS from oneprovider and UMTS from another provider).

FIG. 4 shows a more detailed view of the cellular bypass (CBP). Eachbypass device BPD includes filters that pass the CATV traffic (5-750/860MHz) to the CATV amplifier, and that pass the cellular traffic to thecellular amp. The cellular uplink and downlink traffic is not at thenormal cellular frequencies, but is shifted to another frequency bandthat is typically lower than the normal transmission frequencies, buthigher than the CATV programming. As shown in FIG. 4, the shifted uplinkand downlink traffic is amplified and then rejoined to the cable at theother bypass device BPD.

The CBP may also be referred to as a cellular transport module (CETM)because it transports the cellular signal through the CATV network. TheCETM is installed at any active component of the CATV network, bypassingthe trunk amplifiers, line extenders and distribution modules. The CETMin FIG. 4 is thus a bi-directional amplifier repeater that amplifies theshifted up-link and shifted downlink cellular signals. It may alsoamplify LO (local oscillation) carriers (described below). Thebi-directional amplification of the shifted cellular signals is done ateach point on the CATV network where a CATV amplifier is installed,since the standard CATV amplifier cannot handle the shifted cellularuplink and shifted downlink signals as is. The CETM repeater should belinear enough, in order to prevent distortion of the cellular signals.Its gain should not vary too much across the 75 MHz band in eachdirection. The CETM may get its energy from the CATV network, in whichcase it should be very efficient with minimal power supply.

According to a specific embodiment, the CETM may be installed even whenan active component like a CATV amplifier is not present. That is, theCETM may be employed in situations in which only the cellular signalsneed to be amplified.

FIG. 5 shows the network coupling device NCD and the cable mountcellular antenna CMCA. The NCD simply passes the CATV traffic (860 MHzand below, for example) to the set-top box STB, and passes the cellulartraffic (above 860 MHz, for example) to the CMCA. The CATV and cellularsignals, when together, may be thought of as a combined signal.

The CMCA includes an up and down converter UDC for converting thecellular frequencies from the shifted frequencies to the normalfrequencies according to the particular standard or standards being usedfor cellular communications. Likewise, the UDC also takes normal cellfrequencies and converts them to shifted frequencies for transmissionalong the cable. The UDC may also be referred to, more simply, as afrequency converter.

The CMCA, in particular, takes downlink communications and converts themfrom their shifted form, as received from the cable system, to theirnormal unshifted frequencies. Also, it takes uplink communications andconverts them from their normal unshifted frequencies, to shiftedfrequencies for transmission along the cable system to the appropriatePLMN.

The up and down converter UDC is coupled with an antenna forcommunicating with a mobile terminal at the normal cellular frequencies.

The UDC may include more than just one frequency converter module, andmight have several.

FIG. 6 shows a cellular entrance module (CEEM) 110. A BTS 60 fromcellular system A and a BTS from cellular system B are each connected tothe CEEM. System A is a GSM1800 system in this example, and system B isa UMTS system. The two systems A and B may be from the same or differentproviders.

FIG. 7 shows how these two systems can both be accommodated at the sametime in the bandwidth of the CATV system.

FIG. 7 shows, as an example, the UMTS (for system B) and GSM1800 (forsystem A) frequencies before and after the frequency conversion. That isto say, the GSM 1800 system (system A) is frequency translated so thatthe uplink traffic occupies the part of the shifted uplink signals(UPLINK in the upper part of the figure) indicated by A. This GSM 1800system (A) is also frequency translated so that the downlink trafficoccupies the part of the shifted downlink signals (DOWNLINK in the upperpart of the figure) as indicated also by A.

Likewise, the exemplary figure shows how the signals of UMTS system Bare frequency translated into the shifted uplink signals and the shifteddownlink signals that are carried over the unused frequencies of theCATV system. In the figure, the symbol “R” indicates a reservedsub-band, which may be used for any particular purpose. Each part of theuplink band and the downlink band is thus referred to herein as asub-band.

FIG. 8 shows an alternative frequency shifting approach to illustratethe fact that many variations are possible within the invention, andthat the method described herein is very flexible. In particular, inFIG. 8, the shifted cellular downlink signals are carried in the rangeof, e.g., 960 MHz to 1035 MHz, and the shifted uplink signals arecarried in the range of, e.g., 1080 MHz to 1155 MHz.

The location of the uplink and downlink bands can be varied to suit thepreferences of the local CATV provider, to provide sufficient isolationbetween the shifted cellular signals and the CATV signals, and toprovide sufficient isolation between the shifted uplink and the shifteddownlink cellular signals.

The widths of the uplink and downlink bands may also be varied, and alsothe widths of the sub-band's may likewise be varied and need notnecessarily be uniform in width.

Returning to FIG. 6, the BTS 60 from GSM1800 system A is connected to anup/down frequency converter 210 which converts downlink GSM1800 signalsfrom their original unshifted cellular format to a shifted format inaccordance with the predetermined frequency shifting approach or plan(such as those in FIG. 7 or 8). The downlink signals from system A arethus shifted to the part of the downlink band set aside for system A.

The BTS 60 from UMTS system B is connected to a frequency converter 210which converts downlink signals from their original unshifted cellularformat to a shifted format in accordance with the predeterminedfrequency plan. The downlink signals from system B are thus shifted tothe part of the downlink band set aside for system B.

Likewise, the frequency converters 210 convert the shifted cellularuplink signals from the shifted format (i.e., from the frequencies inthe uplink bands set aside for the particular systems) to their normalformat (i.e., into GSM 1800 or UMTS frequencies).

It will be appreciated that the CEEM receives original cellular signalsfrom a plurality of base stations, and converts the original cellularsignals to a shifted format in a sub-band in accordance with apredetermined frequency shifting plan, and passes the shifted downlinksignals to a CATV system. Similarly, the CEEM receives shifted cellularsignals from the CATV system, and converts the shifted cellular signalsto an original format in accordance with the predetermined frequencyshifting plan, so as to output original cellular signals to respectiveones of the base stations.

The base stations participate in different respective cellular systems(i.e., a GSM 1800 system for system A, and a UMTS system for system B),and the sub-bands may thus each carry the traffic for a differentservice provider and/or a different system.

Each up-link or downlink sub-band may be translated independently byusing a different local oscillator in the respective UDC 210 of theCEEM. Guard bands between the sub-bands are not shown in the figure forthe sake of simplicity. However, if guard bands are needed between thesub-bands, the local oscillator frequencies can be set so as to createthem.

The sub-bands are created out of the original standard frequencyallocation of mobile radio systems. The bandwidth of the sub-band to betranslated is not limited by the examples shown herein. The mobile radiosystem provider may offer to transport up to all the bandwidth he ownsby this system.

FIG. 9 shows a frequency converter UDC for a CMCA in accordance with thesystem in FIGS. 6 and 7 or 8. In particular, the UDC is adapted for asituation in which a GSM provider and a UMTS provider are accommodatedat the same time over the cable system. The shifted cellular signals arecommunicated as shown at the top of the figure via a combiner (for theuplink signals) and a divider (for the downlink signals).

The downlink signals are converted in a known manner to an intermediatefrequency (with local oscillators F1/F5), and then converted to thenormal cellular frequencies for GSM and UMTS, respectively (usingF3/F7). These are passed on to the antenna unit ANT.

Likewise, the uplink signals are received from the antenna unit ANT andconverted in the known manner (using F4/F8) to an intermediatefrequency, and then converted (using F2/F6) to the shifted cellularfrequencies and combined for carrying over the CATV network.

Because the CMCA in this example handles two different systems, it maybe thought of as a cable mount dual band module (CMDBM). Also, becausethe CMCA in this example handles 3G type traffic, it may be described asa cable mount third generation module (CMTGM). Both manners ofdescription are appropriate, although the more generic term CMCA will beused throughout this description because the delivery of signals from anarbitrary number of systems and of any wireless type is an importantobjective.

As can be understood from the foregoing, precise Local Oscillators (LO)are needed. The local oscillator frequencies can be injected to thesystem at the CEEM, and carried along the path to the CMCA. Such LOfrequencies may be referred to as pilot tones. The CMCA can use this LOsignal to convert the cellular up and down link signals to/from theiroriginal standard frequencies. Transporting the local oscillatorfrequencies along the network to the CMCA eliminates the need for usingprecise and expensive frequency sources in the CMCA. This can reduce thecomplexity and cost of the CMCA for the subscriber. Of course, thismethod of transporting the LO frequencies is preferred but not required,and precise local oscillators may be provided in the CMCA.

Some service providers might want to supply only single band service tosome of their customers. A single band module can co-exist with otherdual- or triple-band (or greater) modules connected to the samemulti-band upgraded CATV network. The same premises may have a singleband module in one CATV outlet, and a dual-band module in a differentCATV outlet, elsewhere in the house or office.

FIG. 9 shows a UDC arranged for use in a CMCA, but it will be readilyapparent to those familiar with this field that a substantially similararrangement could be used as the UDC in the CEEM shown, for example, inFIG. 6, but with the uplink and downlink paths in the appropriatedirections.

FIG. 9 shows a frequency converter UDC adapted for handling two systems(and thus having two frequency converter modules), but the same approachcould be taken for handling any arbitrary number of systems. Likewise,performing the intermediate frequency conversion could be performed evenif only one system was being supported.

An example with three systems will now be presented.

In FIG. 10, systems A and B are as in the previous example, but now anadditional system, system C, has been added. System C is a GSM 900system. The CEEM 110 in FIG. 10 therefore has a third frequencyconverter 210 to which a BTS for the system C is connected. Downlinksignals from the GSM 900 system are shifted by this frequency converterin accordance with the frequency plan shown in FIG. 11.

At the bottom, FIG. 11 shows the original, unshifted uplink and downlinkbands for the various cellular communications systems being consideredhere. Above that, FIG. 11 shows the downlink and uplink bands to whichthe cellular signals are frequency shifted. In the top part of thefigure, a more detailed view of the uplink and downlink bands is shown,including the sub-bands.

FIG. 11 is somewhat similar to FIG. 7, and very similar to FIG. 8,except that one of the sub-bands is now dedicated for system C. In thisexample, the arrangement in which the shifted downlink cellular signalsare carried at a frequency below the shifted cellular uplink signals isused, the downlink band being between 960 and 1035 MHz, and the uplinkband being between 1080 and 1155 MHz.

FIG. 12 shows a CMCA suitable for use in this example. That is to say,the CMCA has a UDC with three different UDC modules, one for each of thedifferent cellular systems. In particular, UDC module A is a converterfor GSM 1800 signals, UDC module B is a converter for UMTS cellularsignals, and UDC module C is a converter for GSM 900 cellular signals.Each of these modules converts the original, unshifted uplink cellularsignals to the appropriate sub band, and vice versa.

Now, an example will be provided in which there are six different basestations connected to a CEEM.

In FIG. 13, six different cellular systems are represented. Systems Aand B are GSM 1800 systems. System C is a GSM 900 system. Systems D-Fare UMTS systems. Each of these six systems has a BTS 60 connected tothe CEM 110. Each is connected to a respective UDC 210. The respectiveUDC 210 for each BTS performs frequency conversion in accordance withthe plan shown in FIG. 14, which shows how the different sub bands havebeen set aside for the use of each system. FIG. 15 shows a CMCA suitablefor use in this example. The CMCA has a UDC with six UDC modules. Eachof the six UDC modules is responsible for frequency conversion of thecellular signals between the original unshifted format and the shiftedformat in accordance with the frequency plan shown in FIG. 14. It willbe appreciated that the six systems may be provided from the same ordifferent providers, or combinations of providers.

One familiar with this field will understand that the use of theequipment and method described herein constitutes a method for enhancingthe throughput of second and third generation cellular networks. Withindoor cells accessed through the cellular CATV network, the power ofthe transmitting mobile units indoors can be very low. This, coupledwith the inherent attenuating effects that occur within buildings,combine to make it possible for a much better data service in indoorcells.

The various embodiments and aspects of the system described herein helpovercome the previously described coverage and capacity constraints nowfaced by operators of cellular mobile radio networks. By mitigatingthese coverage constrains, the cost of providing excellent radiocoverage is reduced and service levels are improved. CATV systemoperators will have a potential new source of income. New servicepackages are possible in which CATV and mobile radio terminal serviceare combined.

Although the invention has been described above using some concreteexamples for the sake of explanation, it will be appreciated that theseexamples and the enclosed figures are not intended to limit the scope ofthe invention, which is to be determined based on the appended claims.Many minor modifications and changes will occur to those familiar withthis field, and may be made without departing from the scope and spiritof the invention.

1. A method for providing multi-band bidirectional wireless RF cellularcommunication through a CATV network, comprising: providing a bypassdevice at an active point in a CATV network; and communicating frequencyshifted wireless RF cellular signals and CATV signals, over the CATVnetwork, between an access point of the CATV network and an indoortermination point of the CATV network, wherein the CATV signals arecommunicated via the active point and the shifted wireless RF cellularsignals are communicated via the bypass device; wherein the frequencyshifted wireless RF cellular signals comprise multi-band traffic.